The State Security Services has asked a federal high court to grant it the permission to detain the publisher of Sahara Reporters, Omoyele Sowore, for 90 days.
Mr Sowore, an activist and presidential candidate of the African Action Congress in the 2019 elections, was arrested in Lagos early Saturday by SSS operatives.
The government accused him of planning to overthrow the Buhari government after Mr Sowore called for nationwide protests to enthrone good governance in the country.
The police inspector general, Mohammed Adamu, said the call for a "revolution" constituted an "act of terrorism".
The protests, under the #RevolutionNow banner, held in different cities, including Lagos and Abuja, on Monday despite Mr Sowore's arrest.
The government responded with immense force, with armed security officers attacking and brutalising protesters and journalists who attempted to cover the events.
Prominent Nigerians have condemned Mr Sowore's arrest and the clampdown on peaceful protesters, with some accusing the Buhari administration of curbing civic rights in ways not seen since 1999.
On Tuesday, an Abuja Division of the Federal High Court said it will on Thursday rule on the application filed by the SSS, according to the News Agency of Nigeria.
The SSS said it would need to keep Mr Sowore in its custody beyond the constitutional 48 hours to conclude investigation.
The counsel to the SSS, G. O. Agbadua, told Justice Taiwo Taiwo that a video clip evidence had been attached to its application for more time.
Mr Taiwo adjourned the matter until August 8, saying he needed more days to watch the video clip before delivering his ruling, NAN reported